TA Instruments DSC Q Series, Руководство по началу работы

Страница: 59 / 76

DSC Q Series Getting Started Guide
59
Burning Off Contamination in a DSC Cell with an RCS or LNCS
• Begin cleaning by heating the cell with an air purge to 50°C above the highest operating temperature (400°C
maximum for the RCS 40) or 550°C, whichever is lower, without pans with the cooling accessory ON. Use
a heating rate of 20°C per minute. The Ramp test can be used for this method. Volatile contaminants can be
removed at lower temperatures; decomposed contaminants must be oxidized above 550°C.
WARNING: Do not exceed 100°C with the RCS cooling head installed and the RCS power
off. Serious damage and/or injury could occur.
CAUTION: We recommend that you do not use the RCS 90 when running isothermal
experiments above 400°C. Damage to the unit can occur if used at high temperatures
for extended periods. The RCS 40 cannot be heated above 400°C.
• After cool-down, lightly brush out the cell with a small fiberglass brush (included in the DSC accessory kit).
Then remove the residue from the cell using clean compressed air.
• Run a baseline (empty cell). If there is an improvement relative to the baseline before “burn off” but the
baseline is still unacceptable, repeat the procedure above. If you need to hold longer at the higher temperature
to remove the contamination, you will need to remove the RCS or LNCS heat exchanger before conducting
this experiment. You will also need to temporarily change the selected cooler type to FACS on the
Instrument
Preferences/Cooler Page. (Don’t forget to reselect the correct cooler type after performing this experiment.)
NOTE: When removing the RCS/LNCS heat exchanger from the cell, it is recommended that
the RCS or LNCS be allowed to warm to room temperature after turning it “off” before removing
the heat exchanger. That will minimize the chance for moisture condensation/contamination
and will avoid the possibility of damaging the connector hose by moving while cold (and brittle).
• Removing the heat exchanger requires that the DSC-RCS/LNCS system be reconditioned and recalibrated
after reassembled on the cell.
• Minor baseline anomalies due to sample contamination that remain after cleaning may be compensated for
by a new Tzero calibration. They cannot be compensated for by a Q20/Q10 baseline calibration.
If the baseline problem remains, it is probably not due to contamination; the cell may need to be replaced
(contact your TA Instruments service representative).
• Once the baseline is acceptable, return to normal operation.